This invention relates to the formation of images on media. More particularly this invention relates to the movement of media in a media path.
Typically, in imaging devices, such as inkjet printers, units of media are loaded sequentially into a media path so that after a first unit of media is moved into the media path, a second unit of the media is not moved into the media path until an imaging operation is completed on a first unit of media. One way in which throughput in an imaging device can be defined is as the average rate at which units of media move through the media path during an imaging operation. The time delay between a trailing edge of the first unit of the media and a leading edge of a second unit of the media contributes to a reduction in the throughput of the inkjet printer because this time delay can correspond to a substantial portion of the length of a unit of media. To improve the throughput of the inkjet printer, successive units of the media can be moved into the media path so that the time delay between the trailing edge of the first unit of the media and the leading edge of the second unit of the media is reduced. Operating in this mode can introduce difficulties in the process of moving media through the media path. A need exists for a way in which control the movement of media through the media path in an imaging device while operating in a mode in which successive units of media are rapidly loaded into the media path.
Accordingly, a method for locating an edge of media in an inkjet imaging device has been developed. The method includes moving the media backward in the media path and making a plurality of measurements of light reflected from within the media path while moving the media. The method also includes stopping movement of the media if the plurality of measurements indicates detection of the edge.
An apparatus to move media in an inkjet imaging device includes a sensor configured to measure light reflected from the media. The apparatus also includes a media movement mechanism configured to move the media in a media path. Furthermore, the apparatus includes a processing device arranged to receive a plurality of measurements of light reflected from within the media path from the sensor and configured to command the media movement mechanism to selectively move the media backward or forward in the media path to detect an edge of the media using the plurality of measurements.
An imaging device includes a printhead to eject ink onto media and a printhead controller configured to provide a signal to the printhead to eject ink according to image data. The imaging device further includes a sensor configured to measure light reflected from the media and a media movement mechanism configured to move the media in a media path. The imaging device also includes a processing device arranged to receive a plurality of measurements of light reflected from within the media path from the sensor and configured to command the media movement mechanism to selectively move the media backward in the media path or forward in the media path dependent upon the sensor indicating an absence of the media in the media path from the plurality of measurements, and configured to supply the image data to the printhead controller.